1. Field of the Invention
The present invention relates generally to moving stairways or escalators. More particularly, the invention concerns a novel connector mechanism for use in interconnecting an escalator system between spaced apart floors of a building.
1. Discussion of the Prior Art
Prior art moving stairways or escalators escalators typically include a support truss and a plurality of interconnected steps that travel in a loop within the truss to provide a continuous movement along a specified path. When the escalator assembly is appropriately mounted between the floors of a building, relative motion of course exists between the moving steps and the stationary structure of the conveyor system. If the escalator assembly is rigidly mounted between the adjacent floors of a building and no provision is made for relative movement between the escalator assembly and the building structure catastrophic failures can occur during an earthquake. For this reason various states including California have adopted specific seismic requirements for escalators.
The California Elevator Code adopted in October, 1998 includes seismic requirements for escalators that require that escalators be connected to their structural supports in such a way as to be capable of resisting specified code seismic forces and, at the time, be sufficiently free to move so that they will not be damaged by the relative movement, called xe2x80x9cstory driftxe2x80x9d, of the building structure at the upper and lower landings of the building that are spanned by the escalator assembly.
The latest version of the elevator code, ASME AI7.1, which has not yet been adopted in California, will substantially increase the story drift requirements.
While the existing prior art escalator assembly designs are capable of meeting present code requirements, they will not be capable of meeting the new, more stringent code requirements when they are adopted. Accordingly, the thrust of the present invention is to provide a novel escalator assembly design that will be capable of meeting the substantially more stringent story drift requirements presently to be enacted.
Certain presently existing escalator assembly designs of which applicant is aware accommodate story drift by providing special connection mechanisms at each of the building landings that permit some limited movement between the escalator assembly and affixed to building construction. One form of such prior art connection mechanism includes a first specially designed structural steel member that is interconnected with the escalator structure and a second specially designed, cooperating structural steel member that is interconnected with a fixed structural component of the building structure. More particularly, one of the first and second structural steel members is provided with a rib portion and the other is provided with a slot that receives the rib portion. With this construction the rib portion is free to move within the slot thereby permitting some limited motion between the escalator assembly and fixed structural components of the building structure. While this approach is satisfactory to accommodate small amounts of story drift, it does not provide sufficient structural freedom to safely accommodate substantially greater story drift such as that envisioned by the proposed California codes.
Another prior art escalator assembly design that has been proposed to accommodate story drift requirements caused by earthquakes is disclosed in U.S. Pat. No. 6,129,198 issued to Nusime. The Nusime patent discloses an elevator assembly wherein a first end of the carrier is provided with a bed support which is in turn supported upon a bed formed as part of the building construction by a resilient mounting element which provides damping for vibration and the like passing between the escalator and building construction. A second end of the carrier is similarly provided with a bed support, which is supported upon a fulcrum firmly mounted to the bed. The fulcrum may be in the form of a bolt upon which the bed support is detented. Damping means may be incorporated into the fulcrum construction.
The present invention contemplates an entirely new and novel escalator connection that will both adequately support the escalator system and will accommodate substantial story drift.
It is an object of the present invention to provide an escalator or moving stairway that is constructed to absorb oscillation and lateral displacement of a first story relative to a second story of a building between which the escalator or moving stairway extends such as may occur during an earthquake.
Another object of the invention is to provide an escalator or moving stairway of the aforementioned character that includes novel connector mechanisms at each floor that are connected at one end to a structural support of the building and are connected at the other end to a supporting truss of the escalator.
Another object of the invention is to provide an escalator of the class described in which the novel connector mechanisms of the invention include cooperating telescoping sections that accommodate movement in both tensile and compressive modes in response to forces generated by an earthquake.
Another object of the invention is to provide an escalator as described in the preceding paragraphs in which the novel connector mechanisms include restraint means for limiting the extent of travel in both the tensile and compressive modes.
Another object of the invention is to provide an escalator or moving stairway as described in the preceding paragraphs in which the novel connector mechanisms include an interconnection means that permits limited movement of the escalator or moving stairway relative to the building construction in response to lateral forces generated by an earthquake.
Another object of the invention is to provide an escalator of the class described in which the novel connector mechanisms permit movement of the escalator relative to the building structure in both a longitudinal and transverse direction and also permits pivotal movement of the escalator relative to the building structure.